London: Royal Society of London, 1884/1890. Hardcover. First Edition. vii, 495, viii, 561, xxiv pp. 8vo. Green cloth bindings with burgundy title patch and gold titling to spine of each volume, call number handwritten in white ink at base of each spine. Wear and scuffing to both from library use. Ex-library with bookplate and library stamp on title page of each volume, some library stamps within. Numerous plates illustrate articles. Very Good.
Franz Arthur Friedrich Schuster (1851–1934) studied the curved trajectory of cathode-ray particles (which he hypothesized were electrically charged atoms) in a magnetic field, and formulated an algebraic relationship between their charge/mass (e/m) ratio and their velocity. Later, in 1890 he estimated the upper and lower bounds for this ratio. This was the first step towards the discovery of the electron.